Hormones in Your 40s: What’s Changing and Why It Matters

Ah, your 40s—a time of confidence, wisdom, and, let’s be honest, a body and hormones that suddenly feel like they’re playing an elaborate prank on you. One minute you’re feeling fine, the next you’re crying because you saw an old dog in a movie trailer.

Sound familiar?

That’s because after 40, your hormones start shifting in ways that can leave you feeling like an entirely different person. And jeez, it was such a shock for me.

I’m going to break it all down for you—so you’ll have a clear understanding of what’s actually happening in your body. Next time you hear someone casually mention “balancing your hormones,” you’ll be ahead of the game. You’ll know exactly what those hormones are and what they do—because I’m here to teach you.

Oestrogen & Progesterone: The (Formerly) Dynamic Duo

Your sex hormones oestrogen and progesterone are like best friends; they used to keep everything running smoothly, but now, they seem a little unreliable. As you move through your 40’s, oestrogen starts fluctuating wildly—some days, it’s high, making you feel bloated and irritable, and other days, it’s so low that you find the kettle in the fridge (Brain fog!).

Meanwhile, progesterone (your calming, sleep-promoting hormone) is steadily declining, leaving you with increased anxiety, mood swings, and those delightful 3 a.m. wake-ups for no apparent reason.

The impact on your period? Irregular menstrual cycles, heavier or lighter periods, night sweats, and the distinct urge to throttle your partner for breathing too loudly.

Cortisol: The Stress Hormone That’s Hijacking Everything

Cortisol, your body’s primary stress hormone, is designed to keep you alert in emergencies—but chronic stress keeps it running on overdrive. And when cortisol stays high, it triggers a cascade of hormonal chaos:

Progesterone plummets: Your body prioritises making cortisol over progesterone, meaning at times of hightened stress, your body may be making even less progesterone – our calming, sleep-promoting hormone.

Blood sugar rollercoaster: High cortisol makes you more insulin resistant, leading to sugar cravings and stubborn belly fat.

Sleep disruption: Elevated cortisol at night means more tossing, turning, and waking up at ungodly hours.

Managing stress isn’t just about “self-care”. It is essential for protecting your hormonal balance and longevity.

Testosterone: Not Just a ‘Man’s Hormone’

Testosterone plays a crucial role in energy, motivation, and muscle tone. After 40, it starts declining, and can leave you feeling sluggish, less driven, and noticing a decrease in muscle mass. If you’ve been wondering why workouts feel harder or your libido seems to have taken a vacation, this could be why.

The good news? Nutritional and lifestyle strategies can help support healthy testosterone levels.

Insulin: The Key to your Sudden Belly Fat

Insulin’s job is to regulate blood sugar, but as we age, we can become more insulin-resistant, meaning our bodies aren’t using & storing glucose (aka the breakdown product of our carb-rich foods) as effectively. The result? More stubborn belly fat, energy crashes, and the dreaded “I only LOOK at a cupcake and gain weight” phenomenon.

Balancing insulin means focusing on whole, fiber-rich foods, prioritising protein, and ensuring caffeine isn’t replacing actual meals (as much as we’d all love to count coffee as a food group lol). Exercise is also a powerful tool for helping to support our insulin regulation. A gentle 15 minute walk after meals may help.

Thyroid: The Master of Metabolism (That’s Slowing Down)

Your thyroid is like your body’s thermostat, regulating:

• metabolism
• energy
• temperature
• mood

In your 40s, your thyroid may start lagging, leading to weight gain, fatigue, brain fog, and feeling cold (or hot) even when everyone else is comfortable.

An under-active thyroid can mimic the same symptoms as perimenopause, so it’s important to get that ruled out if you’re feeling off. If this sounds familiar, checking in with a health professional for a full thyroid function test can provide clarity.

Note: we offer blood test analysis appointments in our clinic in Croydon and online Australia wide to current and new clients – this can be an absolute gamechanger for understanding what’s going on in your body as we analyse blood tests against optimal ranges, not just the standard reference range which is used to identify if you need thyroid medication.

How It’s All Connected (Because, of Course, It Is)

Think of your hormones like a group chat—when one starts acting up, it throws off the whole dynamic. If insulin resistance increases, oestrogen dominance can worsen. If thyroid function slows down, metabolism drops, affecting energy and weight. And when oestrogen, progesterone, and testosterone decline, everything from mood to muscle tone to sleep can take a hit.

It’s not just one hormone misbehaving—it’s a tangled web of interactions that requires a big-picture (we call it holistic in the natural healthcare world) approach to balance.

What You Can Do to Support Your Hormones

Thankfully, you’re not at the mercy of your fluctuating hormones. Small, strategic changes can make a world of difference:

Eat Balanced Meals:

Think protein, complex carbs and healthy fats

Strength training:

Important for reducing muscle loss, supporting metabolism, and testosterone levels.

Prioritise sleep:

(easier said than done, I know). We will come back to how to improve your sleep quality on another blog.

Manage stress:

this is an important one! Cortisol (your stress hormone) messes with everything, so deep breathing, walking, and boundaries are your new best friends.

Navigating perimenopause

Yes, things are changing, but that doesn’t mean you’re doomed to feel tired, cranky, or like a stranger in your own body. By understanding what’s happening and making small, sustainable shifts, you can support your hormones and feel so much better.

Are you ready to explore what’s really going on for you? Book in a free 15 minute discovery call with me & let’s have a chat about what working together & creating an individualised treatment plan for you might look like.

More than just one on one:

We know that one on one consultations simply aren’t right for everyone, and that’s why we are in the process of putting together some really great resources for those of you who would prefer to watch webinars or do self-paced online courses. Please keep an eye on our Health Hub to see what we have available. We also have a great collection of free resources which you can download here. By joining the mailing list we will also let you know when new resources are uploaded.